THE CHANGING COASTLINE

Hokitika Guardian, 12 March 1931, Page 7

THE CHANGING COASTLINE

(The “Dominion.”)

Almost every severe earthquake w this conn try works substantial changes in the level of the ocean floor and alters the contour off the sea coast. Several of the great upheavals in the past SO years have forced up the bo.I cf the sea and brought to the surracc new peninsulas and strange reels. Rocks hitherto submerged at low water are now visible at high tide. Towering cliffs against which the waves once dashed incessantly arc now hundreds of yards from the breaking surf, sperated by low-lying tracts of land that appeared suddenly under subterranean pressure.

The majority of these changes have happily been confined to the mainland or to submarine obstructions close to the shore. Rut they constitute a very sound reason for suggesting that early attention should be given to a re-sur-vey of the Now Zealand coast, part of which has not been charted since Captain Cook 'felt his way carefully round its rugged sounds and treacherous inlets on bis visit to the newlydiscovered land itt 1770. Master mark tiers who ate not familiar with these, shores have often complained that the nautical, charts of New Zealand coastal waters are inaccurate and inadequate, miles out of reckoning upon vital points, and ignoring altogether the presence of many well-known marine dangers.

One of the worst shipwrecks that lias ever occurred close to New Zealand —the Joss of the Elingatnite In 1002—was caused primarily by an error in the charted position of the Throe Kings. Tli c Kaipara Rock, in the llauraki Gulf, fortunately quite well known to shipmasters who trade their vessels regularly to these waters, was not marked on the charts many years ago when a French cruiser struck it nor later when the steamer Waimate grazed it, nor even when its namesake, the ship Kaipara, was piled up on it. To-day, despite its hidden dangers, the rock is marked on tiie chart “reported but not examined.”

Some of tlie charts conflict; others frankly admit their complete inaccuracy. Tho Ariel Rocks, off the east coast of the North Island, are shown on two separate charts in positions approximately it mile and a half apart As it is impossible for both positions to 1)0 correct, the captain who took his bearings “blind,” and allowed the usal safety margin of a mile and a half, would in all probability find his snip perched precisely upon the rocks. One nautical map which professes to covet the whole of otll' coastal waters makes the confession : “Soundings in fathoms, Nolo—The positions of most of the points on this chart differ both in latitude and longitude from the latest determination by the New Zealand Government.”

The mariner who reads in his nautical almanac that “the following bearings will place a ship a full inlie •from the breakwater in seven fathoms” at Tiniaru, South Island, finds on laying out the position on his chart that these hearings will anchor his ship exactly on the breakwater. The chart is a mile and a half out, hut fortunately, on the side of safety. Until lie acquires this local knowledge however, lie can rely upon neither the chart nor the almanac, and for safety sake lie is compelled to engage the services of a coastal pilot white he is trading in New Zealand waters. Waipapapa Light, protrudes into the sen two miles farther than the chart indicates. From Palliser Bay to Wellington is practically an uncharted stretch of water, even though it lies in tli o direct route of all shipping approaching Wellington from tfie east. Along the west coast of the South Island the absence of reliable soundings is notorious.

tn a country like New Zealand, crossed as it is hv several well-defined earth faults, where the mighty forces of Nature are for ever at work beneath the surface, it is disconcerting to shipmasters to know that their charts and guide books are inaccurate upon essential points and that one of these errors might at any time lead them into serious difficulties. It would perhaps he a costly undertaking to re-map the whole of the New Zealand coast. But the palpable inadequacy of existing charts and the r« nfficting Information they contain help to justify the claim of visiting mariners that some of the dangerous mistakes should be corrected and the job put in hand without delay. •It is not flattering to reflect that flic Dominion has achieved a certain

notoriety among mariners on account o'P its badly-charted coast. Everything should lie done to dispel that impression and to remove as far as possible the ldddcn rerils that lie off our shores. Much of the work con'd. n»» doubt, he done from the air. The rapid development of aerial methods of survey has made it possible to cover the most erratic coastline quickly and easilv. and without many of the irksome difficulties inseparable from a snrvev hv sea.

Shipping interests consider this expenditure would he justified. Furthermore they expect it in the interests of the trade they represent, and for the safety of the shins and the passengers they carry. The Government mav demur that it cannot at present afford mi expensive survey hut it should ask rather whether it can afford not to undertake it.